Idiopathic Parkinson's
disease (iPD) is a multi-
system disorder, and the debilitating motor stage of iPD can be preceded for years by a prodromal stage characterized by non-
motor symptoms like REM
sleep behavior disorder (RBD) and gastrointestinal symptoms. Widespread
immune dysregulation has been reported in clinically diagnosed iPD, but the existence of immune deficits during the prodromal stage has yet to be thoroughly investigated. Here, it was shown that
multiple stages of iPD, including the pre-motor prodromal stage, can be stratified according to the immuno-metabolic response to stimulation of
peripheral blood immune cells
ex vivo.
Peripheral blood monocytes from RBD patients displayed increased stimulation-dependent
secretion of inflammatory cytokines, including TNF, IL-1β, and IL-8, which peaks in the prodromal stage and successively diminishes as PD progresses. Furthermore,
T lymphocyte mitochondrial health was correlated with stimulation-evoked
cytokine secretion across patients with RBD, early-stage iPD, and moderate-stage iPD. The results disclosed here have broad implications for mechanistic understanding of how
peripheral inflammation may drive
disease progression, and it reveals novel biomarkers to enable
patient stratification and progression monitoring for clinical trials based on immune endophenotypes.